Design and Use of a Novel In Situ Simultaneous Thermal Analysis Cell for an Accurate “Real Time” Monitoring of the Heat and Weight Changes Occurring in Electrochemical Capacitors

Heß, Lars H.; Bothe, Annika; Balducci, Andrea

doi:10.1002/ente.202100329

Cited by 14 publications

(14 citation statements)

References 46 publications

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“…The STA cell was designed to be used in existing STA devices combining thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The EDLC cell consisted of two AC electrodes with Al foil current collector separated by a glass fiber separator impregnated with 1 M Pyr 14 BF 4 in PC [43]. The larger cumulative heat generation and loss of mass at higher cell voltage were consistent with the faster decrease in capacitance attributed to the electrolyte decomposition and evaporation [43].…”

Section: Operando Calorimetrymentioning

confidence: 93%

“…The EDLC cell consisted of two AC electrodes with Al foil current collector separated by a glass fiber separator impregnated with 1 M Pyr 14 BF 4 in PC [43]. The larger cumulative heat generation and loss of mass at higher cell voltage were consistent with the faster decrease in capacitance attributed to the electrolyte decomposition and evaporation [43].…”

Section: Operando Calorimetrymentioning

confidence: 93%

“…Finally, Hess et al [43] developed an open in situ STA cell to measure simultaneously the heat flow, mass loss, resistance, and capacitance of an EDLC cell during cycling or float tests. The STA cell was designed to be used in existing STA devices combining thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC).…”

Section: Operando Calorimetrymentioning

confidence: 99%

“…These mechanisms included (i) ion desolvation and adsorption [39][40][41][42], (ii) overscreening effect [39,40], (iii) organic solvent decomposition [42], and (iv) irreversible ion intercalation in AC electrode under different temperatures and potential windows [42]. Moreover, a new in situ cell was developed for simultaneous thermal analysis (STA) to measure simultaneously heat dissipation and weight changes as well as resistance and capacitance in an EDLC device during cycling or float tests [43]. However, few operando calorimetry studies have used calorimetry to investigate hybrid supercapacitors [32,44].…”

Section: Introductionmentioning

confidence: 99%

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Calorimetry Can Detect the Early Onset of Hydrolysis in Hybrid Supercapacitors with Aqueous Electrolytes

Frajnkovič¹,

Likitchatchawankun²,

Douard³

et al. 2022

SSRN Journal

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Section: Operando Calorimetrymentioning

confidence: 93%

Section: Operando Calorimetrymentioning

confidence: 93%

Section: Operando Calorimetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calorimetry Can Detect the Early Onset of Hydrolysis in Hybrid Supercapacitors with Aqueous Electrolytes

Frajnkovič¹,

Likitchatchawankun²,

Douard³

et al. 2022

SSRN Journal

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“…designed a cell for use in thermogravimetric/differential thermal analysis, which allowed them to investigate the changes in heat flow, mass loss, internal resistance increase, and capacitance loss during cycling and floating of propylene carbonate‐based supercapacitors. [ 79 ] They found a significantly greater increase in the cumulative heat and faster mass loss when the supercapacitors were floated at 3.5 V cell voltage, compared to 2.5 V. This was attributed to irreversible exothermic degradation reactions of the electrode–electrolyte interphase leading to the formation of volatile decomposition products. Coinciding with previous results shown by calorimetry, dilatometry, and DEMS, this technique enables the complementary monitoring of heat and mass variation during electrochemical and/or thermal aging for the first time.…”

Section: Failure Mechanisms Of Electrolytesmentioning

confidence: 99%

The Many Deaths of Supercapacitors: Degradation, Aging, and Performance Fading

Yambou

Köps

Kreth

et al. 2023

Advanced Energy Materials

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High‐performance electrochemical applications have expedited the research in high‐power devices. As such, supercapacitors, including electrical double‐layer capacitors (EDLCs) and pseudocapacitors, have gained significant attention due to their high power density, long cycle life, and fast charging capabilities. Yet, no device lasts forever. It is essential to understand the mechanisms behind performance degradation and aging so that these bottlenecks can be addressed and tailored solutions can be developed. Herein, the factors contributing to the aging and degradation of supercapacitors, including electrode materials, electrolytes, and other aspects of the system, such as pore blocking, electrode compositions, functional groups, and corrosion of current collectors are examined. The monitoring and characterizing of the performance degradation of supercapacitors, including electrochemical methods, in situ, and ex situ techniques are explored. In addition, the degradation mechanisms of different types of electrolytes and electrode materials and the effects of aging from an industrial application standpoint are analyzed. Next, how electrode degradations and electrolyte decompositions can lead to failure, and pore blocking, electrode composition, and other factors that affect the device's lifespan are examined. Finally, the future directions and challenges for reducing supercapacitors' performance degradation, including developing new materials and methods for characterizing and monitoring the devices are summarized.

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Improving the Stability of Supercapacitors at High Voltages and High Temperatures by the Implementation of Ethyl Isopropyl Sulfone as Electrolyte Solvent

Köps

Kreth

Leistenschneider

et al. 2022

Advanced Energy Materials

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promising technologies. [1] EDLCs display high power densities and extremely high lifetime which makes them the technology of choice for a variety of applications requiring a fast and continuous delivery of energy. However, as the energy density of these devices is rather limited (5-8 Wh kg −1 ), their use is currently limited to applications that require a relatively low amount of energy. [2] As indicated by several studies, an increase in energy density would lead to a drastic increase in the number of possible applications for EDLCs. [3] Furthermore, it would enable the use of these devices as replacement for established battery systems in fields where high power is required. [4] This latter application is particularly interesting because nowadays the use of batteries in high-power applications is typically leading to increased cell degradation and, consequently, to increased cost due to early system failure. For this reason, in the available electric vehicles, EDLCs are often applied as a support to reduce the load on the main battery system during rapid acceleration and power uptake by regenerative braking. It has been shown that this hybrid energy storage solution results in improved performance while extending the lifetime of the battery system. [5] Nonetheless, further improvements are urgently needed to extend the battery life even more.For these reasons, current research focuses on the development of EDLCs with improved energy density. To reach this goal, the electrode capacitance needs to be maximized and, at the same time, the operating voltage of these systems needs to be significantly increased. While commercially available devices are limited to operating voltages of up to 3.0 V, an increase to 3.2 V or more would increase the energy density significantly. The operating voltage of EDLCs is mainly determined by the onset of electrolyte decomposition at the electrode surface. [6] The state-of-the-art electrolytes consist of solutions containing ammonium-based conducting salt, e.g. tetraethylammonium tetrafluoroborate (TEABF 4 ), dissolved in acetonitrile (ACN). [7] These electrolytes display high conductivity but guarantee high stability only if used in devices with a maximum voltage of 3 V. [8] With the aim to overcome this limitation and realize high-voltage EDLCs, a variety of novel solvents, salts, and ionic liquids have been investigated in the last years. [9] Although Two of the main weaknesses of modern electric double-layer capacitors are the rather limited ranges of operating voltage and temperature in which these devices do not suffer from the occurrence of irreversible decomposition processes. These parameters are strongly interconnected and lowering the operating voltage when increasing the temperature is unavoidable, so as to protect the electric double-layer capacitor from damage. With the aim to maintain the operating voltage as high as possible at elevated temperatures, in this study, the application of ethyl isopropyl sulfone as an electrolyte solvent for electric double-layer ...

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Design and Use of a Novel In Situ Simultaneous Thermal Analysis Cell for an Accurate “Real Time” Monitoring of the Heat and Weight Changes Occurring in Electrochemical Capacitors

Cited by 14 publications

References 46 publications

Calorimetry Can Detect the Early Onset of Hydrolysis in Hybrid Supercapacitors with Aqueous Electrolytes

Calorimetry Can Detect the Early Onset of Hydrolysis in Hybrid Supercapacitors with Aqueous Electrolytes

The Many Deaths of Supercapacitors: Degradation, Aging, and Performance Fading

Improving the Stability of Supercapacitors at High Voltages and High Temperatures by the Implementation of Ethyl Isopropyl Sulfone as Electrolyte Solvent

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